TRANSillSSIBILITY OF FUNCTIONAL MODIFICATIONS 101 



This is certainly ingeniously and cleverly thought out, and it reads 

 even better and more smoothly in the original than in my brief 

 summary, but it will hardly be regarded as a refutation of my 

 position; the hypotheses are all too daring for that. We have no 

 knowledge that particular modifications in form can be produced and 

 conditioned by particular kinds of food, and, indeed, the contrary has 

 been proved, namely, that the two or three different castes of poly- 

 morphic species have precisely similar diet. I need only recall the 

 sis forms of female in Papilio merope, of which at least three have 

 been obtained from the same set of eggs, and by feeding with the 

 same plant. 



It is true that there are ants which lay in stores of nourishment, 

 but these consist, for the most part, of one kind of seeds, or of honey, 

 not of different substances, and we have no knowledge that the 

 different persons use difierent food, or even that there is any diversity 

 in the mode of feeding the helpless larvse. The feeding in some 

 species takes place from mouth to mouth, and therefore cannot be 

 precisely investigated, and we can only suppose from analogy with 

 bees that the larvse of the males and females frequently receive not 

 only more abundant, but qualitatively different food. They are fed 

 from the crop unless the food consists of the pith of a tree in which 

 the larvEe are imbedded, as Dahl informs us is the ease with some 

 tropical ants of the Bismarck Archipelago. 



But even if we assume that the soldiers take different food from 

 the ordinary workers, and different again from that of the sexual 

 animals, is it by virtue of the quality of their food that they have 

 become what they are ? Have our breeds of pigeons or hens been 

 produced by different diet, or do we know anything in the whole 

 range of animal life of such a parallehsm between food and bodily 

 structure as Zehnder here assumes 1 And if, in reality, let us say, the 

 breeds of pigeon had arisen through specific dieting, and we were to 

 feed one pair with the specific food-stuffs of three different breeds, 

 would the descendants of this pair exhibit the form of these three 

 breeds 1 Or would they exhibit them in precisely the proportion in 

 which the food-stuffs had been mixed 1 It seems to me that Zehnder 's 

 assumptions diverge so far from what we are accustomed to regard 

 as solid ground in biology that they hardly require consideration, and 

 yet he not only uses them for the explanation of the case of the ants, 

 but bases upon them the whole of his theory of the inheritance of 

 acquired characters. 



He considers that the results of use (that is, increased function) 

 are generally transmitted, because the increase in the organ which is 



Digitized by Microsoft® 



